A qubit, or quantum bit, is the basic unit of information in a quantum computer. Unlike a classical bit, which can be either 0 or 1, a qubit can exist as 0, 1, or a combination of both simultaneously through the principle of superposition.

What are the key principles of quantum computing?

Quantum computing relies on three main principles: superposition, which allows qubits to exist in multiple states simultaneously; entanglement, where qubits become correlated with one another; and quantum interference, which amplifies correct computational outcomes while suppressing incorrect ones.

What is decoherence in quantum computing?

Decoherence is the loss of a qubit's quantum state due to interactions with its environment, such as heat, electromagnetic radiation, or vibrations. It introduces errors and limits the reliability of quantum computations.

What is the difference between physical qubits and logical qubits?

A physical qubit is the actual hardware-based qubit in a quantum processor. A logical qubit is created by combining multiple physical qubits using quantum error correction techniques, making it more reliable for fault-tolerant quantum computing.

What are the major challenges facing quantum computing?

The major challenges include decoherence and quantum noise, the need for extensive quantum error correction, and dependence on advanced hardware such as qubit-grade materials and cryogenic systems, which remain under development in many countries including India.

What is India's National Quantum Mission?

The National Quantum Mission is a Government of India initiative launched in 2023 and implemented by the Department of Science and Technology with a budget of ₹6,003.65 crore through 2031. It aims to develop indigenous quantum technologies, including quantum computers, quantum communication, quantum sensing, and quantum materials.

What are the objectives of the National Quantum Mission?

The mission aims to develop quantum computers with 50 to 1,000 physical qubits, establish secure quantum communication networks exceeding 2,000 km, implement Quantum Key Distribution over 2,000 km, develop multi-node quantum networks, quantum sensors, atomic clocks, and advance quantum materials for future technologies.

How is the National Quantum Mission implemented?

The National Quantum Mission is implemented through four Thematic Hubs focusing on Quantum Computing, Quantum Communication, Quantum Sensing and Metrology, and Quantum Materials and Devices. These hubs operate using the Hub-Spoke-Spike model to promote collaboration among research institutions.

Indian Lab Designs Quantum Computing Algorithm to Beat Classical Computers

Q: What is the BITS Pilani and IBM Quantum breakthrough?

Scientists from BITS Pilani, in collaboration with IBM Quantum, successfully simulated the behaviour of subatomic particles on 120 qubits of an IBM quantum processor. The achievement demonstrates Quantum Advantage by showing that quantum computers can outperform classical supercomputers for certain specialised computational tasks.

Q: What is Quantum Advantage?

Quantum Advantage is the stage at which a quantum computer performs a specific computational task faster, more accurately, or at a lower cost than the most powerful classical supercomputers. It applies only to certain complex problems and does not mean quantum computers are better for every task.

Q: What is quantum computing?

Quantum computing is an advanced computing technology that uses the principles of quantum mechanics to process information. Instead of classical bits that represent either 0 or 1, quantum computers use qubits that can exist in multiple states simultaneously, enabling them to solve certain complex problems more efficiently.

Devesh
Jul 13
5 min read

In a significant breakthrough for India's quantum technology ecosystem, scientists from BITS Pilani, in collaboration with IBM Quantum, have successfully simulated the behaviour of subatomic particles on 120 qubits of an IBM quantum processor. The achievement demonstrates Quantum Advantage, showcasing the ability of quantum computers to outperform even the most powerful classical supercomputers in specific computational tasks.

IBM Quantum: IBM's quantum computing platform that provides access to quantum processors and software for research, experimentation, and application development.

Quantum Advantage

The BITS Pilani–IBM collaboration highlights the achievement of Quantum Advantage.

Quantum Advantage: A stage at which a quantum computer performs a specific computational task faster, more accurately, or at a lower cost than the most powerful classical supercomputers. It does not mean quantum computers are superior for all tasks, but rather for certain highly complex problems.

The successful simulation of subatomic particle behaviour on 120 qubits demonstrates the growing capability of quantum computers in solving problems that are computationally intensive for classical systems.

What is Quantum Computing?

Quantum Computing is an advanced field of computing that exploits the principles of quantum mechanics to process information and solve problems that are beyond the capabilities of even the most powerful classical computers.

Quantum Mechanics: The branch of physics that studies the behaviour of matter and energy at the atomic and subatomic levels, where particles exhibit unique properties that differ from classical physics.

Unlike classical computers, which process information using bits, quantum computers use qubits.

Bit: The basic unit of information in a classical computer, which can exist in only one of two states—0 or 1.

Qubit (Quantum Bit): The fundamental unit of information in a quantum computer. Unlike a classical bit, a qubit can exist as 0, 1, or a combination of both simultaneously (superposition), enabling quantum computers to perform many calculations in parallel.

Quantum computing derives its computational power from key principles of quantum mechanics:

Superposition: The ability of a qubit to exist in multiple states simultaneously, allowing parallel computation.
Entanglement: A phenomenon in which two or more qubits become intrinsically linked, so that the state of one qubit is instantly correlated with the state of another, regardless of the distance separating them.
Quantum Interference: The process by which probability amplitudes combine to reinforce correct computational outcomes while cancelling incorrect ones, thereby improving the likelihood of obtaining the right answer.

Together, these properties allow quantum computers to solve certain optimisation, simulation, cryptography, and material science problems much more efficiently than classical computers.

Challenges with Quantum Computing

Despite its immense potential, quantum computing faces several technological and engineering challenges.

1. Decoherence and Noise

One of the biggest challenges is decoherence, where qubits rapidly lose their quantum properties due to interactions with the surrounding environment.

Decoherence: The loss of a qubit's quantum state because of external disturbances such as heat, electromagnetic radiation, or vibrations, leading to computational errors.

In addition, quantum noise introduces random errors, reducing the accuracy and reliability of quantum computations.

2. Error Correction

Quantum systems are highly susceptible to errors, making quantum error correction essential.

However, creating one reliable logical qubit requires a large number of physical qubits.

Physical Qubit: The actual hardware-based qubit present in a quantum processor.

Logical Qubit: A highly reliable qubit created by combining multiple physical qubits through quantum error correction techniques, enabling fault-tolerant quantum computation.

As a result, today's quantum computers require significantly more physical qubits than the number of logical qubits they can effectively use.

3. Hardware Dependence

India's domestic capability in manufacturing critical quantum hardware is still developing.

The indigenous fabrication of:

Qubit-grade materials, and
Cryogenic systems

remains at a nascent stage.

Cryogenic Systems: Specialised cooling systems capable of maintaining extremely low temperatures (often close to absolute zero), which are essential for the stable operation of many quantum processors.

Dependence on imported hardware poses challenges for large-scale deployment and technological self-reliance.

National Quantum Mission (NQM)

Recognising the transformative potential of quantum technologies, the Government of India launched the National Quantum Mission (NQM).

The Mission is being implemented by the Department of Science and Technology (DST) with a total budget of ₹6,003.65 crore for the period 2023–2031.

Objectives of the National Quantum Mission

The Mission seeks to establish India as a global leader in quantum technologies through the following objectives:

1. Development of Quantum Computers

Develop indigenous quantum computers with 50–1,000 physical qubits, enabling advanced research and practical applications.

2. Secure Quantum Communication Infrastructure

Develop a secure, high-bandwidth quantum communication network covering more than 2,000 km.

Quantum Communication: Communication that uses the principles of quantum mechanics to ensure highly secure transmission of information.

3. Inter-city Quantum Key Distribution (QKD)

Establish Quantum Key Distribution (QKD) over a distance of 2,000 km.

Quantum Key Distribution (QKD): A secure communication technique that uses quantum mechanics to exchange cryptographic keys. Any attempt to intercept the key changes its quantum state, immediately revealing the presence of an eavesdropper.

4. Development of Quantum Networks and Precision Technologies

The Mission also aims to develop:

Multi-node quantum networks
Quantum magnetometers
Atomic clocks

Quantum Network: A network that connects quantum devices using quantum communication channels to exchange quantum information securely.

Magnetometer: An instrument used to measure the strength and direction of magnetic fields with high precision.

Atomic Clock: The world's most accurate type of clock, which measures time using the natural frequency of atoms and is widely used in GPS, telecommunications, and scientific research.

5. Development of Quantum Materials

The Mission seeks to develop quantum materials required for next-generation device fabrication.

Quantum Materials: Advanced materials that exhibit unique quantum properties, making them suitable for manufacturing quantum processors, sensors, and communication devices.

Implementation Mechanism

The National Quantum Mission is being implemented through four Thematic Hubs (T-Hubs) located across premier research institutions in India.

The four T-Hubs focus on:

Quantum Computing
Quantum Communication
Quantum Sensing & Metrology
Quantum Materials & Devices

Quantum Sensing: The use of quantum phenomena to develop extremely sensitive instruments capable of measuring physical quantities such as magnetic fields, gravity, and temperature with unprecedented precision.

Metrology: The science of measurement that establishes standards for accurate and reliable measurements.

These hubs follow the Hub–Spoke–Spike model.

Hub–Spoke–Spike Model: A collaborative research framework in which a central Hub coordinates research with multiple Spokes (partner institutions) and specialised Spikes (focused research groups), enabling efficient resource sharing, interdisciplinary collaboration, and technology development.

The successful simulation of subatomic particles on 120 qubits by BITS Pilani scientists in collaboration with IBM Quantum represents an important milestone in India's quantum research journey and demonstrates the growing potential for achieving Quantum Advantage. Supported by the National Quantum Mission (2023–2031), India aims to build indigenous capabilities in quantum computing, secure communication, sensing, materials, and precision technologies, positioning itself as a major player in the global quantum technology ecosystem.

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